Ok...here goes my opinion on the matter...
Sony aren't THE owners of blu-ray because then the only blu-ray players would be Sony's players right? to make the blu-ray successful, more companies had to be apart of it, which they are, but this is only for the movie side of blu-ray, and i believe Sony has the rights to or have copyrighted the use of blu-ray in a gaming console, atleast i think...
Back to the topic a bit more:
Think for a second....Neither party would want this! a hardware update for the 360 would be silly seeing as it's an old console, at least the oldest of this generation, a hardware update like a blu-ray player just wouldn't seem worth the cost, development, persuading game developers to start doing things for blu-ray too, it's just not worth it, if it was going to happen they would have a easier and more profitable time using a blu-ray system in their next console. Not that Sony would want them doing that. the PS3's biggest wow feature is that it's blu-ray, for the masses, the only difference between PS3 and xbox? dvd is old blu-ray new so blu-ray must be better so PS3 is better cause blu-ray!*, So PS3 wouldn't want to lose it's greatest selling point, the fact that it's the only console to have blu-ray! as for letting Microsoft use blu-rays in the next generation.... pfft. Microsoft are the biggest arseholes going when it comes to this sorta thing, if i was sony i would give the rights to Nintendo aswell just to rub it in the xbox's face.
Oh and yes blu-ray quality is MUCH better when watching movies, but in my opinion there isn't any difference between my xbox version of prototype running through component and my brothers on ps3 through HDMI, which for the more clever of you who could work this out, as a gaming medium blu-ray isn't worth it, for sameish quality at a higher price. so why would microsoft want this?
Well i have rambled on so i'm going to stop now, if your here i'm going to asume you've read all of this so thanks to you, and if you've skipped down to the bottom then your obviously not interested in this topic enough and shouldn't post

Thanks!
*(i know this statement isn't entirely true to the intelligents here at the Escapist but i'm trying to be in the mindset of most of the small brained magpies in the rest of the world)*